Trailer Wiring

What kind of vehical is towing the trailer? I have pulled a trailer with LED lights with my 1999 Ford and they worked just fine.

A correctly set up trailer power source on a vehical should work just fine with any type of lighting devices.

Trailer lights should be set up to use 12 VDC whether they're LED's or not. Four dual-element LED's (which operate at 3 VDC at 20-50 mA) wired in series needs no resistor or current limiter.

thanks all for your reply, i have a MB ml320 cdi 2008 the trailer lights and the trailer is controlled by a SAM, a computer which tells the car that you are now plugged in, monitors the lights, reports if one is not working ect, no problem if you tow with a tahoe, or ford, but porche cayane, land rover VW tourag plus a few others like mercedes have documented problems, etrailer sells a 7pin to 7pin harness which solves the problem untill a software fix, which i believe VW has issued is out, i just wanted to know if anybody has another solution.

David

You got what you paid for. Over priced over complicated crap.

Cant help you unless you send me $10000.

Back in the good old days we just did an occasional walk around to see if all of the lighting and signals were working properly. The only SAM I ever used was a coworker by that name that ran the brakes, blinkers and what not while I did a walk around on the company vehicles and work trailers. He never failed me once and was 100% compatible with every vehicle he was ever in!

You could be right, but i was asking for help with the problem.MB has always been innovative and one sometimes pays for that, that said it is a great vehicle, what do you drive??

David

Stuff that comes factory equipped for trailer towing. Ford mostly. I am mot even sure What an MB is?

I am guessing its a Mercedes Beans but they are only driven by rich yuppies around here! If its towing a trailer I doubt your headed off to the construction site with a 4 ton skid steer on a 20 foot flat bed behind it!

it tows 7200lbs, diesel engine made in America

David

Nice. I had no idea They could pull that much! I stand corrected!

Too bad about the engine though being American made. Is it a fuel pig like everyone else's or are you lucky enough to have the good engines with the foreign design?

I like the Mercedes diesels the put in the big trucks! Many of them get the same fuel mileage as my 3/4 ton pickup while hauling around 10 times as much weight!

You could always install an aftermarket modification. Avoid using the factory plug and disconnect it from the SAM altogether. In place make your brake light connection with a relay. You may have to run one wire to a good power source, but it would get you lights without the headache.

i get 25mpg canadian pulling a 22ft trailer

David

Yea, but do you get to know the people that work at the gas stations as well as us Americans do? I bet not!

We see them almost every day and some times several times in one day if we are busy locally.

But really, it sucks to be us. We already know.

Off topic but I don't care.

Yes i could do a normal wiring, but the SAM does more, it controls trailer sway. monitors braking, and checks lighting, still i will prob put the 7pin to 7pin and wait for mb to upgrade, but also i will do a normal wiring just in case. i went to diesel because of its torque, its mileage and its long lasting engine, as well as enjoying driving past the gas station

david

I have been reading your questions about LED lights. I work on motorcycles and have had similar problems in that LED using less voltage. There are resistors you can use to eliminate the headache. Also a simple fix is to add a regular incandecent bulb to your lights with the ground being common. This will use more voltage )puttimg the output to 12volts) that may help your SAM co-operate with your lights. i have done this many times when installing LED lights on bikes and it works everytime.

I would guess your using the LED lamps that are configured for 12V operation?

If you go out and buy a LED from a electronics shop, and try to hook that up, it would either burn out or explode.

Treat LED's as current devices, and use about 10-15mA of current through them, the voltage of the supply doesn't matter, as long as the current is correct

R=(Vs-Vled)/Iled

Iled = 12mA (0.012)

Vled is about 1.2-1.9v depending on the LED, if you chain LED's, its the total voltage across the LED's your after

With an Incandescent Lamp, you'll be using about 21W or about 1.5-1.8A, the LED would be drawing about 10% of this or so.... so I would guess the "SAM" module would detect a "Lamp Failure"

I build test systems, and in the circuits I have been testing, there has been no signals that get fed back from the LED lighting elements/panels to anywhere on a car.

My Scheffen friend may be able to enlighten us to how they do it, but Hella ones don't

Also, if there is feedback from the trailer about the condition of the lamps/LED's what pin does that come back on?

Most of the pins are used, and if its the "Electric Brake's" pin, thats a output to the Electric trailer brakes, from your braking controller

I would guess MB monitors the current draw of the lighting circuits. Being that LEDs draw much less current, I would only guess that increasing the load would help resolve the issue.

I remember trying to connect an LED light assembly to an old bimetallic flasher before. I tricked the circuit by inserting an inductor parallel with the LED circuit to increase the load. The final fix was to go with a digital flasher though.

It is my understanding from reading that the Trailer Stability Assist is only activated when it detects a trailer connected via the 7 pin plug. The TSA is just a software modification to the electronic suspension and transmission to react more efficiently for a trailer.

Who knows exactly how MB incorporates logic for detecting tail light issues. But is worth adding current to the circuit to get rid of an annoying warning?

Had a problem on a motorcycle changing to led lighting went to a solid state flasher. the "mechanical" flashers don't recogniize the low impedance of leds Check out solid state flashers made by GROTE very helpful people check out their website

Mechanical flashers work by the current of a filiment lamp passing through a bi-metal strip to activate the flasher, a LED typically consumes 12-15mA and an array maybe about <100mA depending on the configuration of the array.

LED brake lighting systems should be fed from 12V from the car's circuit, and the module will control the voltages/current's that each LED "see's"

Many vehicles from about 1990 have a very sensitive wiring system and you need a controll box supplied by trailer accessory companies such as Hoppi . Problem is in some cases is they use one wire for more than one use. They do this by running the power to several lights or accessories and a signal to a controll that operates that accessorie. this way they can use much less wiring but you need to decifer the signals. I was in the hitch business in the 90's when this started and it is very common. You can even blow your ECU if you do not do it correctly. Get the box and lights should work properly.

Go to a store that sells trailer interfaces / wiring kits and purchase the one designed for your vehicle.

there are no trailer kits for the 2008 320 cdi

david

In my opinion it has nothing to do with the LED's they do not know where the power comes from and they are regulated for voltage at the light. Many ways of doing this. In the wiring like I mentioned the manufacturers run lets say one power wire to numerous lights or accessories then they run a signal wire to each accessory. At each accessory there is a receiver and it it receives a signal then it supplies power to that accessory and they do it by sending a signal of some type to the receiver. These receivers can only handle so much power and either they will not function or they fail. Contact some trailer accessory companies to see when they will supply a control box for your vehicle. It is so bad that starting in late 90's Ford gm & Chrysler started to install trailer lighting and brake controller harnes as standard or near standard equipment on the vehicles to be compatible with a trailer. I know some systems take the brake light power from the high mount brake light since it is sometimes isolated. Bottom line you need a trailer expert to advise and he or she will problably call the hitch factory. Good luck

MB monitors the voltage, or currant and if there is a drop it tells you a ligjt is out,and flashes you a message on you instrument panal, there are many SAMs they try to do away with as much wire as possible, then and i dont know how, but the mb electrician told me it uses the stop lights as lights and manipulates the voltage accordingly, it will try to maintain lights, and stop lights, beyond me. all sounds good but somebody forgot to factor in the led lights which are now on a lot of travel trailers.

david

Get a 3 ohm 10W resistor in parallel with LED and see if it helps. You'll have to mount it to metal to remove the heat. Depends on the controller, it may work on the brake light. So you don't need the resistor on constant power.

Its not only problem in trailer. Most cruise control won't work with LED brake light.

Check out this forum: http://www.benzworld.org/forums/w164-m-class/1416612-09-ml-trailer-light-module-leds.html

I build custom LED Turn Tail Stop lights for motorcycles. The problem you are experiencing can be solved by placing the ASIC LED controller module in the system. See LUMILED website for details. This will control the T-T-S within a 12 V system. Use of resistors is a simple way to run it. However, with this you will be running in a CW (constant on) state.

Many thanks to all who are helping me so here is the update. My car was plugged in to the diagnostic and Toronto was viewing, there conclusion was that the problem is solved with the 7pin to 7 pin wiring harness which contains resistors and sold by etrailer as well as many others, they will not do a software update as this is to expensive VW did a software upgrade, anyway we will take it up with MB on monday.

david